Missing stETH conversion

Summary

totalAssets() in ETH staking adapters should convert to the ETH. However this isn't done in for the Lido Eth adapter.

Vulnerability Detail

The StEthAdapater.sol, totalAssets is denominated in ETH. However, the function is missing the step where the STETH balance is converted to ETH. We can look at the SFrxETHAdapter for an example of the correct conversion.

Wrong logic in StEthAdapter.sol - STETH.balanceOf() is not converted to ETH value.

    function totalAssets() public view override returns (uint256) {
        uint256 stEthBalance = STETH.balanceOf(address(this));
        return withdrawalQueueEth + bufferEth + stEthBalance;
    }

Correct logic in SFrxETHAdapter.sol - note the line uint256 balanceInFrxEth = STAKED_FRXETH.convertToAssets(balance); converts the staked_frxEth to a value in frxEth

    function totalAssets() public view override returns (uint256) {
        uint256 balance = STAKED_FRXETH.balanceOf(address(this));
        uint256 balanceInFrxEth = STAKED_FRXETH.convertToAssets(balance);
        return withdrawalQueueEth + bufferEth + balanceInFrxEth; // 1 frxEth = 1 ETH
    }

Impact

Wrong value is always returned for totalAssets and thereforce scale of the Lido Frax adapter. This breaks the entire accounting logic of the Tranches.

Code Snippet

https://github.com/sherlock-audit/2024-01-napier/blob/main/napier-v1/src/adapters/BaseLSTAdapter.sol#L232-L234

Tool used

Manual Review

Recommendation

Convert the stEth balance to the corresponding Eth value.

sherlock-audit / 2024-01-napier-judging

Bandit - Missing stETH conversion #55